Nigel,
I use Champion H10 with a 123 unit in the Roadster.
CTA Sweden suggest: Marchal 5N, NGK BP6HS, Champion H10 or K.L.G. F 50
However no mention is made of the ignition type See: http://traction-owners.co.uk/members_only/tech/Technical_data-11BL_BN.htm
I tried to cross-reference the suppliers compatibility charts but quickly found that they “diverged” and didn’t tie up!
Anonymous